<!DOCTYPE html>
<html class="reftest-wait">
<title>transform-box: content-box, box border mutated</title>
<link rel="match" href="reference/cssbox-ref.html">
<link rel="help" href="https://drafts.csswg.org/css-transforms-1/#transform-box">
<script src="/common/reftest-wait.js"></script>
<script src="/common/rendering-utils.js"></script>
<meta name="assert" content="This should display a square with a black bar at the top whose top-left corner is at 100,100."/>
<style>
#target {
    width: 150px;
    height: 200px;
    margin-left: 300px;
    margin-top: 100px;
    background-color: green;
    border-left: solid 25px black;

    transform: rotate(90deg);
    transform-origin: -50px 0;
    transform-box: content-box;
}
</style>
<div id="target"></div>
<script>
  waitForAtLeastOneFrame().then(() => {
    document.querySelector('#target').style.borderLeft = 'solid 50px black';
    takeScreenshot();
  });
</script>
